README.mdgba-core
Emulation core for the Game Boy Advance.
This system contains the following components:
- ARM7TDMI CPU clocked at ~16.77 MHz
- Implements the 32-bit ARMv4T instruction set (ARMv4 + Thumb)
- PPU (picture processing unit)
- 240x160 LCD display
- RGB555 color with up to 512 colors onscreen simultaneously (256 BG + 256 sprite)
- 4 background layers, 2 of which support rotation/scaling
- Up to 128 sprites per frame, with sprites ranging in size from 8x8 pixels to 64x64
- Supports sprite rotation/scaling
- Bitmap graphics modes that display pixels directly from a frame buffer in VRAM
- Supports a mosaic filter for both backgrounds and sprites
- Supports alpha blending between different layers
- 96 KB of VRAM for storing tile data, tile maps, and bitmap mode frame buffers
- 1 KB of palette RAM
- 1 KB of OAM (object attribute memory) for storing the sprite table
- APU (audio processing unit)
- 1-bit PWM output at ~16.77 MHz
- PWM sample resolution ranging from 9-bit samples at 32768 Hz to 6-bit samples at 262144 Hz (most games use 8-bit at 65536 Hz)
- Two 8-bit PCM channels (Direct Sound)
- Four PSG channels, which are slightly modified versions of the four Game Boy Color APU channels
- Two pulse generators, one with frequency sweep support
- Custom wave channel that plays 4-bit PCM samples in a loop of either 32 samples or 64 samples
- Pseudorandom noise generator
- 288 KB of working RAM, split into 32 KB of fast RAM (IWRAM) and 256 KB of slow RAM (EWRAM)
- 4 hardware timers driven by the CPU clock, with configurable prescalers and intervals
- 2 of these timers can be used to control the sample rate of the APU's Direct Sound channels
- 4 DMA channels
- Game Pak prefetch hardware to speed up code executing out of cartridge ROM
- Support for cartridges with up to 32 MB of ROM
- 16 KB builtin BIOS ROM